The art of making various dynamometers has existed for decades. Continuous improvement in the construction of dynamometers for activities including brake testing, performance testing and emissions testing is evidenced by a series of issued patents including U.S. Pat. No. 5,375,461 to Suzuki, U.S. Pat. No. 4,450,728 to D'Angelo et. al., U.S. Pat. No. 4,468,955 to Yamasaki et. al., U.S. Pat. No. 4,688,419 to D'Angelo et al., U.S. Pat. No. 4,870,585 to Manzolini, U.S. Pat. No. 5,010,763 to Schneider, U.S. Pat. No. 3,277,703 to Cline, U.S. Pat. No. 3,554,023 to Geul, U.S. Pat. No. 6,257,054 to Rostkowski et. al., U.S. Pat. No. 5,193,386 to Hesse, Jr. et. al., U.S. Pat. No. 5,844,145 to D'Angelo, U.S. Pat. No. 5,450,748 to Evans et al., U.S. Pat. No. 4,483,204 to Warsaw, U.S. Pat. No. 4,899,595 to Warsaw, U.S. Pat. No. 3,289,471 to Maxwell, U.S. Pat. No. 3,490,276 to Maxwell et. al., U.S. Pat. No. 5,419,192 to Maxwell et. al., U.S. Pat. No. 4,050,299 to Maxwell, U.S. Pat. No. 3,979,950 to Maxwell and U.S. Pat. No. 3,020,753 to Maxwell.
The use of chassis dynamometers for measuring various variables in automotive performance is widely known in the industry. A chassis dynamometer generally includes a frame, at least one set of rollers supported on a frame and a dynamometer attached to the rollers for the purpose of road load stimulation.
For brake testing, general motoring and driving of chassis dynamometer rollers, much less power is required than is necessary for load testing to measure the vehicle power. Frequently, machines use a motor or electric dynamometer that is capable of both functions, i.e. motoring and absorbing power with the chassis dynamometer. However, with the advent of higher horsepower vehicles, it has become necessary to have machines that require greatly oversized motors or electric dynamometers to provide full vehicle power absorption while still providing the lesser power required for driving the rollers. An additional disadvantage of using a large motor or electric dynamometer is the necessity to dissipate heat generated through a resistive load bank or to regenerate the absorbed power as electrical power. Both these functionalities add undesirable complexity and additional cost to the machine.
Accordingly, the need exists for a motoring chassis dynamometer that is very economic in construction. The motoring chassis dynamometer must be modularly built such that the machine may be easily assembled transported and installed as modules. Similarly, if any repair, maintenance or adjustment is required on the chassis dynamometer, the chassis dynamometer may be capable of easy modular disassembly, repair, maintenance and adjustment. Also, the need exists for a chassis dynamometer to provide test performance surpassing the current and anticipated vehicle capability so that tests of vehicle performance, such as brake testing, transmission testing and full engine power testing for higher horsepower vehicles, can be performed without greatly over-sizing the motor or electric dynamometer. The need also exists to offer alternatives to the currently existing dynamometers to provide the same or greater performance by using a reduced size motor and appropriately sized dynamometer. Finally the need exists to construct chassis dynamometers to allow for testing of both low horsepower and high horsepower vehicles by decreasing construction and equipment cost.
There is increasing concern in the United States about the effect of vehicle emissions on air quality. A number of states and local governments have implemented mandatory emissions testing programs to help identify vehicles that are releasing unacceptable levels of harmful emissions.
To conduct emissions testing, dynamometers are typically used to hold the vehicle stationary while its wheels turn.
U.S. Pat. No. 6,886,811 to Spingett discloses a portable dynamometer station with a vehicle mounted lifting assembly. It includes (a) a vehicle, such as a bus, for transporting the dynamometer, (b) a dynamometer with associated monitoring equipment, and (c) a lifting assembly mounted in the vehicle, for transporting the dynamometer from the vehicle to the ground. The lifting assembly includes (i) an upper support beam, (ii) a lower support beam, (iii) a moving trolley on the lower support beam, (iv) a first hydraulic cylinder for moving the lower support beam and the trolley relative to the upper support beam, (v) a second hydraulic cylinder for raising and lowering the dynamometer or other load from the moving trolley, and (vi) a series of pulleys and cables for movement of the lower support beam, the moving trolley, and the dynamometer or other load.
U.S. Pat. No. 6,860,145 to Bergst discloses a motorized chassis dynamometer machine. In one embodiment, the dynamometer machine includes a fixed frame assembly. At least one roller assembly is mounted on the fixed frame assembly. At least one independent motor assembly is connected to each roller assembly. The independent motor assembly is used for driving the roller assembly. At least one independent loading dynamometer assembly capable of measuring the vehicle input power at each roller assembly is coupled to each roller assembly. In a preferred embodiment, the dynamometer assembly is only operable for loading each independent roller assembly, while the motor assembly is operable for driving each independent roller assembly. The machine has at least one motor controller capable of controlling each independent motor assembly and at least one dynamometer controller capable of controlling each independent dynamometer assembly. Each roller assembly, motor controller and dynamometer controller are in turn controlled and manipulated by an overall controller. The dynamometer machine may further include a torque sensor for each motor assembly and each dynamometer assembly. The torque sensors are used to measure torque reaction, each torque sensor independently measuring torque for each of the roller assemblies.